Synchronous yarn feeding device

Abstract

A synchronous yarn feeding device comprises a yarn feeding drum and a driving belt. The drum is provided with protrusions or studs that are arranged for cooperative engagement with concave surfaces or holes in the driving belt. A portion of the driving belt presses yarn onto the drum such that rotation of the drum and feeding of the yarn are synchronous with the speed of the driving belt.

I claim: 
     
       1. A yarn feeding device for use in a textile machine, said textile machine including a machine body and a frame fixed on said body, said yarn feeding device comprising: a drum rotatably mounted on said frame;   a yarn guiding means movably mounted beside said drum on said frame;   an endless driving belt provided to engage said drum at the outer circumference thereof;   a yarn being fed by said belt on said drum; wherein   said drum includes an outer periphery with a first portion having a first rigid projecting engaging means for engaging a corresponding portion of said driving belt, a second drum portion adjacent said first drum portion for receiving a portion of yarn being fed onto said drum when said drum is engaged with a corresponding portion of said driving belt, and a third drum portion for receiving a portion of yarn being fed off said drum when said yarn guiding means is operatively moved toward said third portion of said drum;   said driving belt includes a first belt portion having a second engaging means for cooperative engagement with said first drum portion and said first engaging means, and a second belt portion having a substantial major portion adjacent said first belt portion for pressing a portion of yarn against said drum second portion as a portion of yarn is fed onto said drum; and wherein   said first engaging means provided on said drum and said second engaging means provided on said driving belt are cooperatively interlocked with each other to maintain the position of said belt second portion relative to said drum second portion in an axial direction with respect to said drum so as to effectively prevent said belt from an axial movement; and   said yarn guiding means is operatively controlled to guide movement of said yarn only in the region between said second drum portion and said third drum portion;   whereby when said yarn guiding means is operatively moved to guide said yarn toward said second portion of said belt and said drum, said yarn will be pressed between and driven by the inner surface of said second belt portion and the outer surface of said second drum portion in synchronism with said driving belt and the rotation of said drum so that a substantially constant and uniform yarn feeding operation is provided; and when said yarn guiding means is operatively moved to guide said yarn from said second portion to said third portion of said drum, said yarn is not driven by said driving belt.   
     
     
       2. A yarn feeding device according to claim 1, wherein said first engaging means comprises a plurality of protruding surfaces and said second engaging means comprises a plurality of engaging concave surfaces for complementary engagement with said protruding surfaces of said first engaging means. 
     
     
       3. A yarn feeding device according to claim 1, wherein said first engaging means comprises a plurality of studs and said second engaging means comprises a plurality of holes for interlocking engagement with said studs. 
     
     
       4. A yarn feeding device according to claim 3 wherein a front portion of each of said studs is tapered. 
     
     
       5. A yarn feeding device according to claim 3 wherein said holes are provided on one side of said driving belt. 
     
     
       6. A yarn feeding device according to claim 5, wherein said studs are provided at one side of said drum outer periphery. 
     
     
       7. A yarn feeding device according to claim 1, wherein said second portion of said drum outer periphery comprises a plurality of protrusions interposed with a plurality of grooves aligned with said driving belt to receive a portion of yarn and to feed said yarn from said belt. 
     
     
       8. A yarn feeding device according to claim 1, wherein said second portion of said drum outer periphery comprises a substantially round outer surface. 
     
     
       9. A yarn feeding device according to claim 1 wherein said second portion of said drum outer periphery comprises a rough surface whereby slippage of said yarn on said surface is inhibited. 
     
     
       10. A yarn feeding device according to claim 1 wherein said second portion of said drum outer periphery comprises an elastic body. 
     
     
       11. A yarn feeding device according to claim 1, wherein said second portion of said drum outer periphery comprises a body having a plurality of convex and concave portions. 
     
     
       12. A yarn feeding device according to claim 1 wherein said outer periphery of said drum comprises a plurality of round bars and said first engaging means comprises a plurality of protrusions interposed between said round bars and projecting out of said drum outer periphery. 
     
     
       13. A yarn feeding device according to claim 1, wherein said first engaging means and said second engaging means are cooperatively interlocked with each other at a predetermined position in an axial direction with respect to the drum. 
     
     
       14. A yarn feeding device according to claim 13, wherein said interlocked position of said first and second engaging means is provided on the upper or lower side of said driving belt and drum. 
     
     
       15. A yarn feeding device according to claim 13, wherein said second drum portion and said second belt portion provide said feeding yarn with a substantially even surface to surface contact between the inner surface of the belt and the outer surface of the yarn to provide uniform yarn tension at each discrete point of outgoing yarn fed from said belt and drum during a yarn feeding operation.